<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>01_字体大小</title>
    <style>

        body {
            font-size: 20px;
        }
        .atguigu1 {
            font-size: 0px;
        }
         .atguigu2 {
            font-size: 30px;
        }
        .atguigu3 {
            font-size: 20px;
        }
        .atguigu4 {
            font-size: 20px;
        }
        .atguigu6 {
            font-size: 16px;
        }
    </style>
</head>
<body>
    <div class="atguigu1">尚硅谷1</div> 
    <div class="atguigu2">尚硅谷2</div> 
    <div class="atguigu3">尚硅谷3</div> 
    <div class="atguigu4">尚硅谷4</div> 
    <div class="atguigu5">尚硅谷5</div> 
    <div class="atguigu6">尚硅谷6</div> 
</body>
</body>
</html>